I have purchased my 1988 Iroc Z 350, stock car.. I think even the same factory plugs...

I would like to do some simple bolt on upgrades and am leaning very heavily towards replacing the stock heads with a set of vortec and the SD Vortec TPI manifold. My impetuousness has caused me to buy the SD Vortec manifold... BEFORE... doing so much reading. I have purchased a dodo bird intake, but Im ok with it... my wifes van is faster than the Iroc and I'm fine with that.

But I would like to at least stay with her.. which means.. intake and heads are it.

I'm done after that. I don't want to go fast, only something a little stronger than stock. My question for the forum is this; what runners will I need for the SD manifold?

again, my search comes up with mixed results, except the article that was done back in 2005... and the article says it was using factory runners. Then, comes the other side of the coin where the threads read that the factory runners did not line up, you need Edelbrock or SLP runners.

Can anyone verify this - a phone call to SD went like this... hold on let me ask my supervisor... a voice in the background replied yes. There you go sir... stock will work.

Thank you,

Bryan

 

Stock will work. Sometimes with aftermarket parts, quality isn't quite as good as stock. I'm guessing this was the issue in question, of course I don't know for sure what they ran into. Look at it this way....you already HAVE stock runners and they don't cost you anything!

...I could mention that aftermarket runners would slightly increase performance as well. ......and some minor plenum porting. ....and minor porting on the base ......and a slightly bigger cam..... ....and valvetrain upgrades..... .....and some head porting..... .....headers..... tuning...... catback..... down.....the rabbit hole.........we go!

 

My son and I have been trying to decipher just what to expect, best guess with stock runners is about 300 HP at the crank, and around 400 foot-pounds. The torque curve is a little broader over stock, which should translate to a noticeable bump in performance. Nothing totally radical, but definitely worthwhile, and an improvement you'll feel. This is exactly what we're doing to my L98 '88, and for his '87 El Camino, once we swap a TPI system on his car.

 

Stock runners breathe better than most people will give them credit. Especially with a Vortec head. Stock L98 cam should come in around 300-310 HP with Vortec heads, 3817 base, and stock runners provided you have a decent set of headers and exhaust for it to breathe out of. Torque should be in the 420-430 ft/lbs range.